含溴离子水臭氧氧化过程中溴酸盐生成影响因素研究

通过纯水条件下的模拟研究,对影响含溴离子水臭氧氧化过程中溴酸盐生成量的水质参数和臭氧投加方式进行了考察.结果表明,溴酸盐的生成量随着臭氧投加量的增加而增加,并与溴离子初始浓度成线性关系.反应温度在15～26℃之间时,溴酸盐生成量随着温度的升高而增加了2倍以上.水体pH在6.0～7.8范围内升高明显有利于溴酸盐的形成,并加速了水中臭氧浓度的衰减.同样的水质条件下,臭氧连续投加相对臭氧瞬时投加可降低约46.5%的溴酸盐生成量.     

四溴双酚A的臭氧氧化降解研究

通过小试试验,考察了臭氧对水体中四溴双酚A的处理效果,并研究了臭氧浓度、pH值和温度等因素对处理效果的影响,试验结果表明:臭氧可以实现对四溴双酚A快速去除,反应符合假一级动力学模型,四溴双酚A的去除率随臭氧投量升高而增大;较低的pH和温度有利于臭氧对四溴双酚A的去除.GC-MS分析发现,四溴双酚A降解中间有机产物主要包...     

含溴水臭氧化过程中溴酸盐的形成与控制

本文总结综述了含溴水臭氧化过程中的主要副产物溴酸根离子的生成途径,生成量的影响因素,以及控制其生成的主要方法,并探讨了饮用水生产中控制溴酸盐生成的可能措施。     

亚硝酸钠催化氧气氧化溴化双酚A制备四溴双酚A

发展了以亚硝酸钠为催化剂,溴素为溴化试剂,通过分子氧氧化溴化双酚A制备四溴双酚A的方法,这是一个新颖、有效的催化氧化方法。考察了溶剂、温度、n(双酚A)∶n(溴素)、催化剂用量、氧气/空气通入时间以及溴素的滴加速度对反应的影响,确定了最佳的反应条件,即:n(双酚A)∶n(溴素)∶n(亚硝酸钠)=1∶2.15∶0.1,反应温度25℃,反应时间2 h。在此反应条件下,四溴双酚A的分离收率可达95.0%(以双酚A计)。该反应具有溴素的利用率高,原子经济性强,反应副产物仅为水,绿色无污染等优点。     

青草沙水库原水中的溴离子和溴酸盐生成势

该文测定了青草沙水库水在蓄水期和运营初期的溴离子,并通过小试试验初步考查了溴酸盐生成势.结果表明,青草沙水库的长江来水含有一定浓度的溴离子(0.4～0.6 mg/L),可通过水库蓄水予以调节.相似条件下青草沙水库水溴酸盐生成势高于黄浦江水.     

四溴双酚A的合成研究

四溴双酚A以95%无水乙醇为溶剂,以双酚A和溴素为原料合成。在双酚A与溴素摩尔比一定的条件下,通过改变反应时间进行合成实验,结果表明:最佳反应时间2.5 h;在反应时间一定的条件下,通过改变双酚A与溴素摩尔比进行合成实验,结果表明:最佳原料摩尔比1∶2.6。在此反应条件下合成具有高收率,高质量,操作简便等优点。     

阻燃剂四溴双酚A的环境友好合成工艺研究

研究了过氧化氢存在下以双酚A与液溴为原料合成四溴双酚A的工艺条件 ,考察了n(Br2 )∶n(双酚A)、n(H2 O2 )∶n(Br2 )、反应时间等因素对反应的影响 ,并通过正交实验 ,优化了合成工艺条件。实验表明 :n(Br2 )∶n(双酚A) =2 2 0∶1 0 0 ,n(H2 O2 )∶n(Br2 ) =1 10∶1 0 0 ,反应温度15～ 2 5℃ ,每克双酚A加水 3mL时收率接近 99% ,溴利用率达 99%     

双酚A合成四溴双酚A双(2,3一二溴丙基)醚的工艺研究

将四溴双酚A和四溴双酚A双(2,3-二溴丙基)醚(简称八溴醚)两产品的工艺技术有机地结合起来,探讨了在氯苯溶剂中以双酚A为原料直接合成四溴双酚钠,并在乙醇溶剂中与氯丙烯合成中间体四溴双酚A双烯丙基醚的过程及分析了各种影响因素,开发出一条由双酚A直接制备八溴醚的工艺路线。该工艺的主要特点是四溴双酚A以钠盐的形态直接转入醚化工序,缩短了工艺流程,减少了溶剂损失。     

甲醇法生产四溴双酚A新工艺

甲醇是生产四溴双酚A合适的溶剂 ,对产品质量有影响的因素有 :溶液温度、酸度和加溴速度。在低温和高酸度下 ,控制一定的加溴速度 ,可以生产出高质量的产品。保持体系一定含水量 ,抑制HBr与甲醇反应 ,用H2 O2 氧化副产品HBr ,可有效降低溴代甲烷的生成量 ,提高溴素利用率。在 85%甲醇水溶液中 ,当原料的配比为 :n(双酚A)∶n(Br2 )∶n(H2 O2 ) =1∶2 .2 3∶1时 ,得到的产品纯度为 99.4 % ,收率 98.5% ,色度 (APHA)为 19,无机溴和水解溴含量为 0 .0 0 4 0 % ,产品熔点≥ 180℃     

四溴双酚A的合成新工艺

对以次氯酸钙为氧化剂合成四溴双酚A的生产工艺做了研究,该工艺具有原料价廉易得、反应条件温和、产品收率高等优点,具有广阔的推广、应用前景。     

Effect of ozonation pretreatment on the surface properties and catalytic activity of multi-walled carbon nanotube

Multi-walled carbon nanotube (MWCNT) has been used in the catalytic ozonation of oxalic acid in aqueous solution, which was pretreated using ozone and was characterized by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption and Boehm titration. The effect of ozonation pretreatment on the catalytic activity of MWCNT and the ozonation mechanism of oxalic acid in the presence of MWCNT were investigated. The results indicate that with the increasing pretreatment time, the atom ratio of oxygen to carbon and the number of surface acid groups on MWCNT increase, while the catalytic activity of MWCNT on ozonation of oxalic acid decreases, suggesting that the chemical characteristics of MWCNT mainly determine its catalytic activity on oxalic acid mineralization. The inhibition of tert-butyl alcohol on the degradation of oxalic acid is slight for pristine MWCNT catalytic ozonation and this inhibition trend becomes more obvious when MWCNT was pretreated by ozone. A free radical mechanism was proposed which involves both surface reactions and bulk reactions between the oxalic acid and active species.     

ACF催化臭氧化降解苯酚的反应参数影响

研究了活性碳纤维(ACF)催化臭氧化降解苯酚过程中各种参数的影响。结果表明,ACF能够显著提高臭氧化效率,当ACF为1g,反应10min时苯酚的去除率为96.8%,而同样条件下活性炭仅为68%;臭氧化效率在酸性下几乎相同并高于碱性下,而且在碱性下随pH值升高而降低;臭氧化空气流量从0.04m3/h增加到0.16m3/h,反应10min时的效率提高为17%;苯酚初始浓度升高到500mg/L仅使臭氧化效率下降不到10%。重复实验表明臭氧化过程中ACF的催化性能可以得到原位再生。     

Effect of pH on inactivation of Microcystis aeruginosa by ozonation air in sequencing batch reactor

In this study, a mixture of ozone and air (ozonation air for short) was adopted for the inactivation of Microcystis aeruginosa in a sequencing batch reactor (SBR). Scanning electron microscopy of Microcystis aeruginosa revealed damage to the cell wall and leakage of intracellular contents after ozone oxidation. Owing to the destruction of cells, the chlorophyll a released from the cells was degraded by ozone oxidation, which showed that chlorophyll a concentrations increased vastly during the first 5 min, then, decreased continuously. pH in the SBR declined with increasing time, reaching around 3.0 at the end of the cycle. It was observed that the removal efficiencies of chlorophyll a were, respectively, 68.4%, 74.5%, 86.7% and 77.9% after 90 min at pH 3.0, 7.0, 9.0 and 11.0 conditions, and the degradation of chlorophyll a accorded with the apparent first‐order kinetics. The results suggested that inactivation of Microcystis aeruginosa was successfully performed by ozone treatment, verifying the potential of this alternative process for the decontamination of eutrophic water. Copyright © 2010 Society of Chemical Industry     

Effect of ozonation on chemical oxygen demand fractionation and color profile of textile wastewaters

Filtration and ultrafiltration with a size range of 2–1600 nm were used to evaluate the effect of ozonation on the particle size distribution‐based chemical oxygen demand (COD) and color profiles of textile wastewater before and after biological treatment. Ozonation induced a net effect of 9% COD reduction in the influent and 15% in the effluent. However, a more in‐depth evaluation based on particle size distribution and mass balance for the influent revealed different mechanisms of ozonation, which were interpreted as total oxidation in the soluble range, replenishment of soluble COD through solubilization of organics into simpler compounds and polymerization towards the upper size range (>220 nm). For the biological treatment effluent, the greatest effect of ozonation was in the lower particle size range (<8 nm). Ozone was very effective for color removal, giving 80–93% optical density reductions in the influent and 96–99% in the effluent, depending on the excitation wavelength selected. Ozonation of the influent removed practically all color fractions, except in the particulate range. In the effluent, the particulate fraction was removed by biological treatment and settling and consequently the remaining color were almost entirely removed by ozonation. Copyright © 2005 Society of Chemical Industry     

混凝沉淀-臭氧氧化深度处理皂素废水的实验研究

用混凝沉淀-臭氧氧化组合工艺对皂素生物处理出水的净化效果进行了研究。结果表明,YJD/PAM对皂素废水有较好的絮凝效果,臭氧氧化处理效果受废水pH、臭氧投加量、反应时间等因素的影响,实验的最佳反应条件为:废水pH值为11,臭氧投加量为1 500 mg/L,反应时间为20 min左右,此时出水COD和色度均达到国家排放标准。     

Fe2O3/改性沸石催化剂的制备及其催化臭氧氧化对氯苯酚

为了提高非均相催化臭氧氧化体系处理难降解有机废水的效率,分别以十六烷基三甲基溴化铵（CTMAB）改性的天然沸石和Fe(NO₃)₃·9H₂O溶液作为载体和活性组分前体,采用浸渍法制备Fe₂O₃/改性天然沸石催化剂（MNZ）,利用能谱仪（EDS）、扫描电镜（SEM）、傅里叶变换红外光谱仪（FTIR）、X射线衍射仪（XRD）、X射线光电子能谱仪（XPS）、N₂-吸附/脱附等方法分析催化剂的结构和组成,研究其催化臭氧氧化对氯苯酚的效果和催化机制。结果表明：Fe₂O₃/MNZ催化剂保持了天然沸石的表面结构。Fe₂O₃均匀负载在沸石表面,属于典型的分子筛结构,比表面积、孔容和孔径分别为12.776m²/g、0.042cm³/g和3.932nm。在对氯苯酚初始浓度为100mg/L、臭氧浓度为2.6mg/L、温度为25℃、pH为7.0±0.2的条件下,对氯苯酚和化学需氧量（COD）去除率分别为87.26%和48.83%。天然沸石与Fe₂O₃共同促进臭氧分解生成强氧化能力的羟基自由基（·OH）,提高了对氯苯酚的去除率,反应体系遵循羟基自由基作用机理。     

多相催化臭氧氧化法处理印染废水的研究

采用浸渍法制备了活性炭负载铁锰氧化物的催化剂用于对印染废水的多相催化臭氧氧化处理,当铁锰质量比为1∶2时,催化剂处理效果最佳。多相催化臭氧氧化工艺的最佳运行参数为:处理时间60 min、臭氧通气量0.2 L/min、催化剂投加质量20 g、废水pH=5。经多相催化臭氧氧化处理后,印染废水的COD、氨氮、TP、色度去除率分别为81.7%、90.2%、97.6%、99.1%,去除效果较好。     

Experimental and theoretical study on catalytic ozonation of humic acid by ZnO catalyst

Ozonation and catalytic ozonation of humic acid (HA) in the presence of ZnO were examined in a batch scale reactor. The degradation of HA by catalytic ozonation was found to be much more effective than ozonation alone. The quantum chemistry calculations showed that the reaction of the O₃ disproportionation on the surface of ZnO corresponds to the barrierless mechanism. The activation energy of the transition state formation was ?5.25 eV. The active oxygen atom formed on the surface of ZnO was found as interacting with both water molecules and dissolved organic molecules, which might lead to further oxidizing reactions.     

Catalysts to improve the abatement of sulfamethoxazole and the resulting organic carbon in water during ozonation

Sulfamethoxazole (SMX), one pharmaceutical compound, has been treated in aqueous solutions with catalysts (copper and cobalt type perovskites and cobalt–alumina) and promoters (activated carbons). Hydrogen peroxide and saturated carboxylic acids were identified as intermediates. The effects of adsorption and pH have been investigated. Removal of the starting SMX accomplished with ozone alone is a fast process but catalytic or promoted ozonation is needed to significantly reduce the resulting organic carbon. SMX is, thus, mainly removed through direct ozone reaction while hydroxyl radical oxidation is the mechanism of removal the remaining TOC. The kinetics of the process has also been investigated. Perovskite catalytic ozonation resulted to be a chemical control process and apparent rate constants for homogeneous and heterogeneous ozonation were determined. For activated carbon ozonation, external diffusion of ozone to solid particles controlled the process rate.